1. Field of the Invention
The present invention relates in general to a magnetic head for use in a hard disc drive (hereinafter, referred to as an HDD). More particularly, the invention relates to the construction of a magnetic head for use in the HDD for which the high recording density has been obtained, a bonding device which is suitably employed in the process of manufacturing the magnetic head, and a bonding method.
2. Related Background Art
In recent years, the recording density of HDDs has been rapidly increased, and the width of each of the tracks as the recording areas in the hard disc as the recording medium has become remarkably narrow combined with the miniaturization of the HDDs. For this reason, with the tracking of the magnetic head by only a voice coil motor which has been conventionally carried out, it becomes difficult to position accurately the magnetic head in this narrow track Thus, there has been proposed the control of the tracking based on the piggy back system.
The conventional magnetic head comprises a core actually writing and reading the recorded information to and from the hard disc, and a suspension for supporting the core. On the other hand, the piggy back system is characterized in construction by providing a fine adjustment actuator between the core and the suspension (hereinafter, referred to as a gimbal). That is, the system of interest is such that the position of the magnetic head is moved to the neighborhood of the desired position of the tracking by the voice coil motor and then, the position of the core is corrected by the fine adjustment actuator, whereby the tracking of the high accuracy is carried out.
As for the construction of the magnetic head for use in the piggy back system, for example, there is one shown in FIG. 4 and FIG. 5. A magnetic head 1 includes a core 10, a gimbal 2 which extends in one direction to support the core 10 at one end thereof, and a fine adjustment actuator 30 which is arranged between the core 10 and the gimbal 2. The gimbal 2 is composed of a flexure 4 formed of an insulating flexible resin thin plate on which a conductor pattern for wiring is formed, a load beam 3 which is formed of a elastic metallic thin plate or the like to which the flexure 4 is adhered, and a base plate 7 which is firmly fixed to the base portion of the load beam 3 as the other end of the gimbal 2.
The head portion of the flexure 4 has an actuator attaching portion 5 which is not adhered to the head portion of the load beam 3, but is arranged so as to lie on the load beam 3 roughly in parallel therewith. The fine adjustment actuator 30 is firmly fixed to the actuator attaching portion 5, and the core 10 is fixed to the fine adjustment actuator 30 so as to be able to pivot in the extension direction of the gimbal 2.
A dimple (a projection portion for abutting from the back face the flexure 4) 6 which is formed integrally with the head portion of the load beam comes in contact with the back face of the actuator attaching portion 5, i.e., the back face of the flexure 4 (refer to FIG. 1). Normally, the fixing of the core 10 and the fine adjustment actuator 30 to the flexure 4 is carried out such that the pivotal center of the core 10 is aligned with the center of the dimple 6.
An element (not shown) including an electromagnetic conversion element and a magnetoelelctric conversion element, and electrodes 11 which are used to draw the electrical signal from that element to the outside are formed on one end face of the core 10. The electrodes 11 are electrically connected to end portions 8 of the electrical wiring provided in the flexure 4 (hereinafter, referred to as a substrate land) through wires 66 each made of Au or the like. In this connection, the flat surface in which the substrate lands 8 are formed and the flat surface on the core 10 in which the electrodes 11 are formed make an angle of about 90 degrees.
As for the method of connecting electrically the electrodes formed on the two flat surfaces making an angle of about 90 degrees as described above, there have been proposed the various methods such as the wire bonding method disclosed in Japanese Patent Application No. 10-56046 and No. 11-235785 by the present applicant, and the ball bonding method employing conductor balls disclosed in Japanese Patent Application Laid-open No. 9-283568 by the present applicant.
As described above, in the construction as well of the magnetic head employing the piggy back system, the electrodes 11 and the substrate lands 8 need to be electrically connected to each other through the wires 66. However, the fine adjustment actuator 30 is present between the core 10 and the flexure 4, and also the fixed distance is defined between the electrodes 11 and the substrate lands 8. Therefore, the ball bonding method disclosed in Japanese Patent Application Laid-open No. 9-283568 is difficult to be applied thereto.
In addition, in the above-mentioned wire bonding method, when bonding the wires 66 to the electrodes 11 and the substrate lands 8, the core 10 and the flexure 4 are clamped by a clamp mechanism to carry out the fixing therefor. However, the fine adjustment actuator 30 is in general weak against the force applied from the outside and hence is readily damaged. Since in the clamp mechanism in the conventional wire bonding method, the fine adjustment actuator 30 is loaded with the force for clamping, the method of interest can not be directly applied to the magnetic head employing the piggy back system.
In addition, while in the magnetic head employing the piggy back system, the core 10 is pivoted by the fine adjustment actuator 30, when each of the wires 66 is short, there may occur the case where the pivotal movement is limited by these wires 66. Therefore, in order to carry out smoothly and accurately that pivotal movement, each of the wires 66 needs to have the flexibility and the sufficient length. Further, against the bending which is applied to the wires 66 by the pivotal movement operation, each of the wires 66 needs also to have the sufficient durability.